From 4f0d505c651a19c6f8b349cafa26a82aaffc8d9b Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Thu, 27 Feb 2020 18:02:40 +0100
Subject: [PATCH] v2: `if x := `; fix `for key, val in`; CastExpr

---
 vlib/v/ast/ast.v       | 23 +++++++++++++++--------
 vlib/v/fmt/fmt.v       | 19 +++++++++++++++++--
 vlib/v/parser/parser.v | 25 +++++++++++++++++++++----
 3 files changed, 53 insertions(+), 14 deletions(-)

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 1e20f9d8e3..236fb895b3 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -11,11 +11,11 @@ import (
 pub type Expr = InfixExpr | IfExpr | StringLiteral | IntegerLiteral | CharLiteral | 	
 FloatLiteral | Ident | CallExpr | BoolLiteral | StructInit | ArrayInit | SelectorExpr | PostfixExpr | 	
 AssignExpr | PrefixExpr | MethodCallExpr | IndexExpr | RangeExpr | MatchExpr | 	
-CastExpr | EnumVal | Assoc | SizeOf | None | MapInit
+CastExpr | EnumVal | Assoc | SizeOf | None | MapInit | OrExpr
 
-pub type Stmt = VarDecl | GlobalDecl | FnDecl | Return | Module | Import | ExprStmt |
-ForStmt | StructDecl | ForCStmt | ForInStmt | CompIf | ConstDecl | Attr | BranchStmt |
-HashStmt | AssignStmt | EnumDecl | TypeDecl | DeferStmt | GotoLabel | GotoStmt |
+pub type Stmt = VarDecl | GlobalDecl | FnDecl | Return | Module | Import | ExprStmt | 	
+ForStmt | StructDecl | ForCStmt | ForInStmt | CompIf | ConstDecl | Attr | BranchStmt | 	
+HashStmt | AssignStmt | EnumDecl | TypeDecl | DeferStmt | GotoLabel | GotoStmt | 	
 LineComment | MultiLineComment | AssertStmt | UnsafeStmt
 
 pub type Type = StructType | ArrayType
@@ -351,10 +351,11 @@ pub:
 
 pub struct ForInStmt {
 pub:
-	var   string
-	cond  Expr
-	stmts []Stmt
-	pos   token.Position
+	key_var string
+	val_var string
+	cond    Expr
+	stmts   []Stmt
+	pos     token.Position
 }
 
 pub struct ForCStmt {
@@ -481,6 +482,12 @@ pub:
 	expr Expr
 }
 
+pub struct OrExpr {
+pub:
+	var_name string
+	expr     Expr
+}
+
 pub struct Assoc {
 pub:
 	name   string
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index fa48120ceb..1114a0282c 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -159,7 +159,11 @@ fn (f mut Fmt) stmt(node ast.Stmt) {
 			f.writeln('}\n')
 		}
 		ast.ForInStmt {
-			f.write('for $it.var in ')
+			f.write('for $it.key_var')
+			if it.val_var != '' {
+				f.write(', $it.val_var')
+			}
+			f.write(' in ')
 			f.expr(it.cond)
 			f.writeln(' {')
 			f.stmts(it.stmts)
@@ -282,6 +286,11 @@ fn (f mut Fmt) expr(node ast.Expr) {
 		ast.BoolLiteral {
 			f.write(it.val.str())
 		}
+		ast.CastExpr {
+			f.write(f.table.type_to_str(it.typ) + '(')
+			f.expr(it.expr)
+			f.write(')')
+		}
 		ast.CallExpr {
 			f.write('${it.name}(')
 			for i, expr in it.args {
@@ -387,6 +396,10 @@ fn (f mut Fmt) expr(node ast.Expr) {
 		ast.None {
 			f.write('none')
 		}
+		ast.OrExpr {
+			f.write(it.var_name + ' := ')
+			f.expr(it.expr)
+		}
 		ast.PostfixExpr {
 			f.expr(it.expr)
 			f.write(it.op.str())
@@ -424,7 +437,9 @@ fn (f mut Fmt) expr(node ast.Expr) {
 				f.write('}')
 			}
 		}
-		else {}
+		else {
+			println('fmt expr: unhandled node ') // + typeof(node))
+		}
 	}
 }
 
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index 721f20f66b..bf3e823896 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -1035,9 +1035,10 @@ fn (p mut Parser) for_statement() ast.Stmt {
 	// `for i in vals`, `for i in start .. end`
 	else if p.peek_tok.kind in [.key_in, .comma] {
 		var_name := p.check_name()
+		mut val_name := ''
 		if p.tok.kind == .comma {
 			p.check(.comma)
-			val_name := p.check_name()
+			val_name = p.check_name()
 			// p.table.register_var(table.Var{
 			// name: val_name
 			// typ: table.int_type
@@ -1092,7 +1093,8 @@ fn (p mut Parser) for_statement() ast.Stmt {
 			stmts: stmts
 			pos: p.tok.position()
 			cond: cond
-			var: var_name
+			key_var: var_name
+			val_var: val_name
 		}
 	}
 	// `for cond {`
@@ -1115,10 +1117,22 @@ fn (p mut Parser) if_expr() ast.Expr {
 	pos := p.tok.position()
 	// `if x := opt() {`
 	mut cond := ast.Expr{}
+	mut is_or := false
 	if p.peek_tok.kind == .decl_assign {
-		p.next()
+		is_or = true
+		p.open_scope()
+		var_name := p.check_name()
+		// p.table.register_var(
 		p.check(.decl_assign)
-		p.expr(0)
+		expr,typ := p.expr(0)
+		p.scope.register_var(ast.VarDecl{
+			name: var_name
+			typ: typ
+		})
+		cond = ast.OrExpr{
+			var_name: var_name
+			expr: expr
+		}
 	}
 	else {
 		cond,_ = p.expr(0)
@@ -1138,6 +1152,9 @@ fn (p mut Parser) if_expr() ast.Expr {
 			else_stmts = p.parse_block()
 		}
 	}
+	if is_or {
+		p.close_scope()
+	}
 	// mut typ := table.void_type
 	// mut left := ast.Expr{}
 	// If the last statement is an expression, return its type